England head coach Stuart Lancaster has revealed that Alex Corbisiero's participation in next month's QBE Internationals is threatened by a knee problem.

Corbisiero, a star of the victorious British and Irish Lions tour to Australia, has had fluid drained from the joint and is a doubt for the Twickenham appointments with Australia, Argentina and New Zealand.

It is a worrying development for a player who has been troubled by repeated knee issues and renews concerns over his long-term future.

Corbisiero missed last season's entire RBS 6 Nations with a similar complaint, returning in time for England's June tour to Argentina, but Lancaster insisted the current problem is with the other knee.

In January the 25-year-old Northampton loosehead was described as having "degenerative knee issues" by Brian Smith, the director of rugby at his former club London Irish.

England's autumn schedule opens against Australia on November 2 and Lancaster stated that the condition will be monitored closely.

"It's recommended that Alex has a couple of weeks' rehab. He's not out of the series by any stretch of the imagination," Lancaster said.

"Everyone is optimistically hoping he will come through and be available for some, if not all, the games.

"At the moment, having had fluid drained off the knee, he will have a period of rehab that covers this week and leading into next week. We'll see how we go, we're keeping an open mind on it.

"Long term it's obviously something he's struggling with, but we're optimistic that with good management - and his club Northampton have been excellent - we'll see him through beyond 2015.

"We're still quite a way away from the Australia game. We'll give him plenty of time but we'll do what's right for Alex."

Mako Vunipola and Joe Marler are the alternatives available to England, but Lancaster will be desperate to have Corbisiero present in the front row.

Standout performances in the first and third Tests for the Lions against Australia confirmed his standing as a world-class loosehead.

His reputation was further enhanced when Vunipola's failings at the set-piece in the second Test - Corbisiero was missing with a calf problem - contributed to the tourists' only defeat in the series.

Lancaster is already without three Lions next month after Tom Croft, Manu Tuilagi and Brad Barritt were ruled out through injury and can ill-afford to lose a fourth.

The replacements for Croft, Tuilagi and Barritt were announced on Wednesday morning with Gloucester centre Henry Trinder the most notable addition having missed out on selection for the elite player and Saxons squads named in August.

Trinder is joined by Saracens centre Joel Tomkins and Exeter flanker Tom Johnson with the presence of Northampton centre Luther Burrell as injury cover increasing the size of the squad for the autumn to 34.

A strong start to the season has given Trinder a genuine of chance of filling the number 13 jersey against the Wallabies, but Tomkins is also hoping to partner Billy Twelvetrees in midfield.

"I've coached Henry quite a few times with the Saxons and he was a key player in our Churchill Cup win a couple of years ago," Lancaster said.

"In the past he's struggled a bit through injuries to get a consistent run of form, but now he's fit and in form, although he has a slight hamstring problem at the moment.

"He's started the season really well and has been playing exceptionally well."